Production of M-/GM-group aflatoxins catalyzed by the OrdA enzyme in aflatoxin biosynthesis

► Biosynthetic pathway of 4 M-/GM-aflatoxins (M1, M2, GM1, and GM2) were clarified. ► Fungus has ability to produce eight kinds of aflatoxins: 4 B-/G- and 4 M-/GM-ones. ► M-/GM- and B-/G-aflatoxins are produced from at least two common precursors. ► OrdA enzyme is involved in the branching step between M-/GM- and B-/G-aflatoxins.